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    <title>Document</title>
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    <script>
        console.log(Math.abs(1));
        console.log(Math.abs(-1));
        console.log(Math.abs('longge'));

        // 三个取整方法
        // 1.Math.floor 向下取整
        console.log(Math.floor(1.1));
        console.log(Math.floor(1.9));
        console.log(Math.floor(-1.1));
        // 2.Math.ceil 向上取整
        console.log(Math.ceil(1.1));
        console.log(Math.ceil(1.9));
        console.log(Math.ceil(1.5));
        console.log(Math.ceil(-1.5));
        // 3.Math.round 四舍五入取整 .5往往都是往大的取整
        console.log(Math.round(1.1));
        console.log(Math.round(1.9));
        console.log(Math.round(1.5));
        console.log(Math.round(-1.5)); 
    </script>
</body>
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